Sen. Al Franken (D-MN) said on Tuesday he would test whether a Senate tradition that his Republican colleagues used to thwart several of President Obama’s judicial nominees will actually be honored now that Donald Trump is in the White House.

A quick primer. When Democrats controlled the Senate, and Sen. Pat Leahy (D-VT) chaired the Judiciary Committee, Leahy would not allow a judicial nomination to move forward unless both of the nominee’s home-state senators returned a “blue slip” agreeing to let the nominee have a hearing. Senate Republicans used this ability to block several of Obama’s judges. Franken has now decided to test whether current Senate Judiciary Chair Chuck Grassley (R-IA) will do Democratic senators the same favor.

In effect, Franken is trying to veto Trump’s nomination of Minnesota Supreme Court Justice David Stras to a federal appeals court, noting his fear that Stras will “steer the already conservative Eighth Circuit even further to the right.” Stras is a former law clerk to conservative Justice Clarence Thomas, who typically hires ideologically similar young lawyers to work in his chambers.